Panels for movable wall systems have traditionally been supported by dollies or trolleys mounted in an overhead track. Individual wall panels in these systems can weigh several hundred pounds each. For systems containing many panels or large panels, the rooms must be provided with very strong and expensive structural support systems that can support the weight of the panels, the overhead track, and related hardware. With increased concern over construction costs, alternatives to overhead-supported wall panel systems are important.
One alternative to overhead-supported wall panel systems is a floor-supported system. With such a system, wheels are mounted on the bottom of each wall panel, and the weight of the panel is supported by the floor of the room. Each panel also has a guide or bolt projecting from the top of the panel, which fits into an overhead track, and which prevents the panel from tipping over. Although an overhead track and its associated hardware are still required, they need not be strong because they do not support the weight of the wall panels.
Despite the advantages of floor-supported wall panel systems, the distance between the bottom of a wall panel and the floor for these systems is difficult to adjust. Obviously, in any wall panel system, the wall panels should extend from just above the floor to just below the ceiling. Flexible seals or sweeps are mounted on the upper and lower edges of the panel to provide a completely solid wall without gaps between opposite sides of the panel, while still minimizing friction so the panels may be easily moved. Thus, the height of a wall panel above the floor must be carefully adjusted when it is installed. In addition, over time, floors and ceilings of building are prone to "deflect," or change their vertical position. Roof deflection can be caused by, for example, heavy snow on the roof of a building, while floor deflection can be caused by a heavy load on the floor. Therefore, it is often necessary to readjust the distance of a wall panel from the floor to account for floor or ceiling deflection.
The height of prior art floor supported wall panels is difficult to adjust. The wheels are located below the panel and are connected by an upwardly-extending threaded bolt to the frame of the wall panel. In order to adjust the height for one type of prior art panel, the panel must be lifted out of its floor guide track and swung to one side of the track, taking care to ensure that the panel does not slip out of the upper track and fall to the floor. The lower guide wheels (and the connected threaded bolt) are then manually rotated to screw the bolt into or out of a nut welded to the wall panel frame. The wall panel is then lifted and tilted so the floor guide enters the floor guide track, again taking care to prevent the panel from tipping over. This procedure is particularly cumbersome when adjacent panels are connected by hinges, as all panels must be tilted out just to adjust the height of one panel.
Another type of height adjustment mechanism for floor-supported wall panels does not require the guide wheels to be rotated. Instead, the nut which engages the threaded shaft from the guide wheels may be freely screwed to any desired vertical position on the shaft. The top of the nut abuts the frame of the panel, so as the nut is rotated to move away from the guide wheels, the wall panel will be raised accordingly. The shortcoming of this system is that the adjustment nut is located within the frame of the panel. Therefore, the panel must be constructed with a hole adjacent to the adjustment nut. In order to prevent unsightly exposure of this hole, a kick plate is screwed onto the lower portion of the panel to cover the hole. However, such kickplates are not only cumbersome to remove and replace, but also add to the cost of the panel and detract from its aesthetic appearance.
Another shortcoming of existing floor-supported wall panels is that it is not possible to include a pass door in such a wall panel unless the panel includes a threshold. This is because floor support mechanisms are positioned in the middle of a wall panel, which is the same location where a pass door is positioned. However, thresholds are undesirable in wall panels because persons are prone to trip over the thresholds when going through the pass door.
It is also known to provide a dolly for an exterior aircraft hanger door in which the dolly includes a spring connecting the dolly to the door. Such a system allows the door to compensate for variations in the height of the ground.